ad hoc 
(ăd hŏk, hōk)
(ăd hŏk, hōk)adv.
For the specific purpose, case, or situation at hand and for no other: a committee formed ad hoc to address the issue of salaries.
adj.
1. Formed for or concerned with one specific purpose: an ad hoc compensation committee.
2. Improvised and often impromptu: "This single little incident reveals volumes about the arbitrariness and ad hoc brutality of the Roman regime" (Harvey Cox).
[Latin : ad, to + hoc, neuter accusative of hic, this.]